How levonorgestrel works
As a progestogen, levonorgestrel influences the body’s regulation of the menstrual cycle. This can be roughly divided into two phases, each of which lasts about two weeks: the follicular phase and the luteal phase.
Ovulation heralds the second half of the cycle, the luteal phase. The ovary or the ovarian follicle that has matured in it releases the egg, which is then taken up by the fallopian tube. It is capable of fertilization for about 12 to 24 hours. The now empty follicle in the ovary transforms into the corpus luteum and starts producing the body’s own corpus luteum hormone progesterone.
If, on the other hand, fertilization does not take place, the corpus luteum shrinks, which means that no more progesterone is produced. With the next menstrual period, the thickened endometrium is then shed and excreted together with the unfertilized egg.
Levonorgestrel as a contraceptive pill
Likewise, levonorgestrel makes the secretion of the cervix more viscous, which makes it harder for sperm to enter the uterus. Natural progesterone could not be used for these purposes because it would be rapidly broken down in the liver after ingestion.
For contraception, levonorgestrel is taken alone or in combination with other hormones (such as ethinylestradiol) in phases or permanently as a “pill” to suit the cycle.
In addition, higher doses of levonorgestrel are also approved as the “morning-after pill”. It can drastically reduce the chance of pregnancy up to three days (72 hours) after unprotected sexual intercourse.
Levonorgestrel as a hormone IUD
The hormonal IUD steadily releases levonorgestrel into the uterine cavity, where it primarily thickens the cervical mucus (cervical mucus). This creates a natural barrier for sperm on their way to an egg.
Levonorgestrel additionally slows down the build-up of the uterine lining, thereby preventing an egg from implanting. In this way, the woman’s menstrual period is often shortened or reduced.
Absorption, degradation and excretion
After ingestion, levonorgestrel is completely absorbed in the intestine and reaches its highest levels in the blood after three hours. If the active ingredient is taken only once (as with the “morning-after pill”), half of the active ingredient is excreted again after about two days.
When taken repeatedly (as a contraceptive pill), the active ingredient accumulates in the body and excretion is delayed.
Levonorgestrel is broken down in the liver and about half is excreted in the urine and half in the stool.
When is levonorgestrel used?
Levonorgestrel is approved for contraception as a hormonal IUD, for oral use as a single agent (known as the “mini-pill”) or in combination with an estrogen (usually ethinyl estradiol).
How levonorgestrel is used
A combined pill containing levonorgestrel and an estrogen is usually used for contraception. It is taken for the first 21 days of the cycle (starting on the 1st day of menstruation), preferably at the same time each day.
The mini-pill, which contains only levonorgestrel, is taken continuously. Women must be even more careful to take the pill regularly. If a woman forgets to take a pill by more than three hours, contraceptive protection is no longer guaranteed for at least seven days.
Caution: This only applies to the minipill as an exception – with other contraceptive pills, never take two tablets at the same time!
An intrauterine device (hormonal coil) with levonorgestrel can remain in the uterus for up to five years. It is therefore preferably suitable for long-term contraception.
Use of the levonorgestrel hormone IUD
Doctors usually insert the hormonal IUD within seven days of the start of menstruation. The levonorgestrel then takes effect immediately. The hormonal IUD can also be inserted directly after miscarriages or abortions in the first trimester.
The doctor checks the position of the levonorgestrel coil at set intervals. The first check is usually four to twelve weeks after the IUD was inserted. The hormonal IUD can be removed at any time, but should be removed after three or five years at the latest, depending on the preparation. It is possible to insert a new IUD immediately afterwards.
To ensure continuous contraception, a new IUD is needed immediately after removal. Alternatively, you can use another contraceptive method (e.g. condom) at least seven days before removal.
How to take levonorgestrel as the “morning-after pill”?
Levonorgestrel must be taken as an emergency contraceptive (“morning-after pill”) as soon as possible after unprotected sexual intercourse, but no later than 72 hours:
What are the side effects of levonorgestrel?
The side effects of levonorgestrel are dose-dependent. They thus occur more frequently at higher doses, most severely with the “morning-after pill”.
More than ten percent of the women treated experience headaches, nausea, pain in the lower abdomen, vaginal bleeding, and fatigue.
The side effects of taking the pill as a contraceptive are usually less frequent and less severe.
The tolerance of the “morning-after pill” can be improved by eating a small meal (e.g. a sandwich) at the same time.
The symptoms of inflamed genital organs are varied. If you notice symptoms, have them examined by a doctor immediately. If left untreated, the risk of severe inflammatory reactions, blood poisoning or impaired fertility increases.
Often, patients also get ovarian cysts, which usually do not cause any symptoms and disappear on their own. Nevertheless, they should always be examined by a doctor, as in some cases treatment is necessary.
Pain or increased bleeding may indicate that the IUD is no longer fitting properly. However, it can also slip or be expelled without the patient noticing. Therefore, it is a good idea to regularly feel for the retrieval threads attached to the IUD. In this way, it is possible to check whether it is still in place. However, this says nothing about whether it is correctly positioned in the uterus.
What should I bear in mind when using levonorgestrel?
Contraindications
- Hypersensitivity to the active ingredient or any of the other ingredients of the drug.
Levonorgestrel as a contraceptive pill must not be taken in addition in the following cases:
- known or suspected pregnancy
- existing thromboembolic diseases (such as deep vein thrombosis, pulmonary embolism)
- previous or existing arterial and cardiovascular diseases (such as heart attack, stroke)
- diabetes with vascular changes
- severe liver dysfunction or liver tumors
- unexplained vaginal bleeding
Levonorgestrel as an intrauterine drug release system must not be used in:
- hypersensitivity to the active substance or other components of the drug
- acute or recurrent inflammation of the internal genital organs such as inflammation of the vagina (colpitis) or cervix (cervicitis)
- pregnancy
- Pathological cell changes or malignant diseases in the cervix (neck of the uterus) or the uterus (womb).
- cancers influenced by sex hormones (e.g. breast cancer)
- malformations of the cervix or uterus that interfere with the insertion or removal of the hormonal coil
- unexplained vaginal bleeding
- severe liver disease or liver tumors
Interactions
Examples of such agents are agents against epilepsy and seizures (such as phenobarbital, phenytoin, carbamazepine, topiramate), agents against infections (such as rifampicin, efavirenz, ritonavir, griseofulvin) and the herbal antidepressant St. John’s wort.
Taking levonorgestrel may increase the risk of heart attacks and strokes in patients with coagulation disorders and in smokers.
Age restriction
Pregnancy and breastfeeding
Pregnant women should not take hormone preparations such as the contraceptive pill (levonorgestrel alone or together with an estrogen) or the “morning after pill”. Accidental use of a contraceptive pill or “morning after pill” during pregnancy does not require further diagnostic testing.
Intrauterine levonorgestrel preparations (hormonal IUD) must not be used during pregnancy.
If you become pregnant with a levonorgestrel IUD, the pregnancy is at a higher risk outside the uterus (e.g. ectopic pregnancy). This risk increases in women who have already had such an extrauterine pregnancy, tubal surgery, or pelvic inflammatory disease.
If you suspect that you are pregnant while using the levonorgestrel IUD, contact your doctor immediately. He will discuss the further procedure with you.
How to obtain medication with levonorgestrel
The “morning-after pill” with levonorgestrel is available without a prescription in Germany, Austria, and Switzerland, as well as in many other European countries, and can be purchased without a prescription after a thorough consultation at the pharmacy.
The contraceptive pill with levonorgestrel, on the other hand, requires a prescription. The hormonal IUD also requires a prescription and is inserted by a doctor.
Since when is levonorgestrel known?
The contraceptive is not patent-protected, which is why numerous pharmaceutical companies market preparations containing the active ingredient levonorgestrel.
